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Is Your Cattle Plunge Doing Its Job, Australians Asked

Using plunge dips for tick control is a necessity in Australia, but the Northern Territory Cattlemen's Association warns that it must be done right to be most effective.

Precision is important with dip formulation, says an Agnote from the Department of Primary Industries.

In extreme cases, high concentrations can deposit chemical residues on meat and low concentrations do not do the job properly.

Dips using higher than the necessary chemical concentration:

a) are uneconomical because they waste expensive chemical

b) can cause death, particularly in young calves and weak animals

c) can deposit residues of the chemical in the meat which could jeopardise our markets, particularly the export market.

Dips using lower than the necessary concentration of the chemical:

a) do not kill many ticks

b) can cause expensive delays in trucking cattle because of the presence of ticks

c) incorrect dip strength can also cause resistance in ticks to the chemical.

Determining the volume of a plunge dip

The first step in good management is to know the volume of liquid in your dip and there are three menthods to determine this:

a) Use a flow meter to measure the amount of water going into the dip. This is the best method and eliminates any guesswork.

b) Fill the dip from a tank of known capacity.

c) Use the formula: Volume = Average length x average width x depth

Other Important Points to Remember

Much time and effort can be saved by accurately marking the various volume levels on the dip wall, or on a measuring stick, such as at 5000 L, 6000 L, 7000 L and so on until the maximum level is reached.

Once the volume of the water in the dip has been calculated, the amount of chemical to be added should be accurately calculated according to the manufacturer’s directions.

DO NOT add a ‘bit for luck’, as this will increase the concentration of chemical in your dip.

After the plunge dip has been used and the level of the mix in it drops, it becomes necessary to top it up with water and chemical.

The topping up rate varies with various chemicals and is always given by the manufacturer.

If you are dipping a large number of cattle, top up the dip with water and chemical after every 400-500 animals have passed through in order to maintain maximum efficiency in your dip.

Before dipping, run at least 30 head of stirrer cattle through the dip to distribute the chemical evenly throughout the dip. These cattle should be returned to the main mob and dipped again.

After Dipping

On completion of dipping, note and record the level of liquid in the dip. Then at the next dipping, again note the level before commencing dipping.

Calculate the difference in volume between the two levels. Variation in the levels between two dipping periods is mainly caused by evaporation during hot weather, or wet season rain that causes the liquid level to rise.

The differences need to be compensated for. A roof over the dip will prevent rain water from entering the dip and will also reduce evaporation.

Measures and Controls

It is sound policy to keep a dip book listing all information related to the use of the dip.

The results of an analysis of the contents of a cattle dip sample are only as good as the sample. If the sample is not collected correctly, it is a waste of time and effort to analyse it.

If you are sure your dip is being maintained at the correct strength and you are still experiencing poor tick control, ask your stock inspector how to collect and handle a sample of ticks for testing for resistance.